Holy Moly! You absolutely nailed it! I've long felt that sound is about 60% of immersion. That is, is, if you have only meh gfx but amazing sfx you're gonna be RIGHT THERE, but the other way around, you'll admire the pretty picture but you won't be transported. There's a CD out there, "Open Pipe Symphony" which captures the sound of a 12-cylinder Ferrari 312 F1 car that raises the hackles on my neck every time I hear it. Google it or:
https://www.youtube.com/watch?v=o_U3cbydv9Y
Every update on my work (Soundmods Tests, Preview and Releases) will be post on my YT Channel and here on RD : https://www.youtube.com/channel/UCoOQ74jfwfXGy3--xo_U96w